University of Moratuwa Research – Reports

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Browsing University of Moratuwa Research – Reports by Author "Amarasinghe, BMWPK"

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    Application of membrane separation processes to the Sri Lankan Industry
    Amarasinghe, BMWPK; De Silva, IMBM
    Membrane separation is a relatively new technology applicable for a range of separations. The technique is attractive due to its ability to produce high quality products, suitability for processing heat sensitive materials and possibility of recovering and recycling of valuables from waste streams. Current applications of membrane separations for liquid systems in the Sri Lankan industry and possibilities for future developments were investigated. The survey shows that only 5% of the industries considered for the survey currently use membrane separations. However, 51% have the possibility of using membrane separations either for water treatment, wastewater treatment or for separations in the manufacturing processes. Normal Filtration and Ion Exchange are the widely used techniques for water treatment. Reverse Osmosis and/or Ultra Filtration can be used for purification of water for medical and pharmaceutical applications, for preparing drinking water and boiler feed water from high salinity water or seawater. Pulp and paper, Textile and Diary industries have the possibilities of using MS for wastewater treatment and recovery and recycle of valuables. However, novel techniques such as PV can be used for removal of tracers of hazardous components. Further, Pervaporation, Osmotic Distillation etc. can be experimented for the manufacture of new range of products in food and biotechnological fields and for obtaining highly purified products. Despite the relatively high capital and maintenance cost and the problems of concentration polarisation and membrane fouling application of the technique for many Sri Lankan industries will be important in anticipation of future demands of high standards and minimal environmental impact.
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    item: SRC-Report
    Coir pith activated carbon for the removal of organics and dyes from aqueous solutions
    (2008) Amarasinghe, BMWPK
    Drinking water sources in developing and underdeveloped countries are facing serious threat from contamination problems due to both man-made industrial and agricultural activities and natural sources such as minerals. In many developing countries ground water is used for drinking purposes and it is pollutes with toxic anions, heavy metals, organic compounds and dyes due to effluent from industries. These unwanted chemicals cause health problems, when they exceed the tolerance limits in water. The removal of pollutants from wastewater can be carried out by Coagulation/Flocculation, Ozonation, Adsorption or membrane separation. Most of these methods suffer from, drawbacks such as high capital and operational cost and there are problems in disposal of sludge. The use of activated carbons to remove tracer pollutants from water is widely extended because of their high surface area, microporous character and the chemical nature of their surface.
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    item: SRC-Report
    Effect of hot air temperature on high moist paddy drying in a conical spouted bed
    (2019) Maduwanthi, MKC; Jayatunga, GK; Amarasinghe, BMWPK
    Parboiled paddy of two varieties namely Samba and Nadu were dried in a lab scale spouted bed dryer. Spouting behaviour, drying kinetics and heat and mass transfer characteristics of parboiled paddy were investigated. The minimum spouting velocity was determined for parboiled paddy of two varieties for three different bed heights. Drying experiments were carried out to analyse the effect of drying temperature and air velocity on drying kinetics, moisture diffusivity and heat transfer coefficient. Results revealed that spouted bed drying operation with elevated temperatures show higher drying rates. The spouted bed dryer spouting at different air velocities had almost similar drying rates at stable spouting state for a selected drying temperature and bed height.
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    Industrial pollution reduction programme : waste minimization project at DCSL Seeduwa
    Amarasinghe, BMWPK; Fonseka, PNP
    Distilleries Corporation of Sri Lanka (DCSL) at Seeduwa produces various brands of Alcohol from toddy such as; a) Extra special arrack - 33.5% vol alcohol, 6 month maturity b) Blue label arrack - 33.5 vol% alcohol, 6-12 month maturity c) VSOA - 36.8 vol% alcohol, 2-3 years maturity d) Double Distilled alcohol - 36.8 vol% alcohol, 2-3 years e) Tappers arrack - 33.5 vol% alcohol, 1 year maturity Approximately 120 hi of abs. Alcohol is produced per day. The plant has a capacity of processing 6.62 m3 of toddy per hr. The objective of the work is to Analyse the process, Identify Waste Minimization options, Suggest suitable waste minimization solutions, Evaluate technical feasibility, viability and environmental aspects and Implement waste minimization options
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    item: SRC-Report
    Low cost packed bed tower scrubbers for gas cleaning and air pollution control
    Amarasinghe, BMWPK
    This is the report submitted to the Senate Research Committee of the University of Moratuwa on the project 'Low Cost Packed Bed Tower Scrubbers for Gas Cleaning and Air Pollution Control'. Cleaning of gases is an extremely important operation in Chemical and Process industries, specially with new environmental rules and regulations. Packed bed scrubbers are very popular and efficient for removal of harmful gases, dust and mist from exit gas streams in process plants. The aim of the project was to examine the possibility of using low cost packing material for scrubbers. Experiments were conducted to test the absorption of C02 to water using two types of packing materials. Based on the results obtained mass transfer coefficient calculated. The theory on scrubbers, experimental procedure, analysis of the results and the design procedure are discussed in the report. was I wish to thank senate research committee of the University of Moratuwa for providing funds for the project. Finally, I wish to thank Mr. B. Hewakandamby, Mr. P. Shabeshe, Mr. G. Jeyakumar and the technical staff of the Unit Operations laboratory for assisting me in setting up the experimental rig and conducting trial
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    item: SRC-Report
    Removal of phenol from wastewater using rice husk based adsorbent
    Amarasinghe, BMWPK
    Phenolic compounds are widely used in industrial sector and contamination of water by such compounds is a major environmental problem. Presence of phenolic compounds in wastewater cause serious discharge problems due to their toxicity and poor biodegradability. Adsorption is proven to be an effective method of removing contaminants from wastewater. This work investigates adsorption of phenol onto thermally treated rice husk from aqueous solutions. Rice husk was washed and thermally treated at 700 DCfor 1 h. Batch experiments were conducted to determine the factors affecting adsorption and kinetics of the process. Thermally treated rice husk is capable of adsorbing appreciable amounts of phenol from aqueous solutions. No significant effect of initial solution pH on adsorption was observed.Experiments on effect of adsorbent particle size on adsorption shows high percentage removal and high rate of adsorption for fine particle size compared to coarse particle size fractions. The adsorbent to solution ratio affects the degree of phenol removal and percentage removal capacities of 40 and 95 were observed with 1 g and 15 g of adsorbent dose per liter of wastewater respectively. The equilibrium data were satisfactorily fitted to Freundlich isotherm and the parameters showed favourable adsorption. Phenol uptake of 16mg per gram of adsorbent was observed when the waste water containing 100 mg of phenol/L is treated with an adsorbent dose of 15 g/L. Tests on phenol removal as a function of time show rapid initial adsorption rate followed by a slower rate. Kinetic data were fitted to the Pseudo second order model and initial adsorption rates and rate constants were determined.